Wednesday, June 21, 2017

Yawns at CERN

Some 5,000 physicists are back at work here at CERN, the European Organization for Nuclear Research, watching their computers sift the debris from primordial collisions in search of new particles and forces of nature, and plan to keep at it for at least the next 20 years.

Science is knocking on heaven’s door, as the Harvard physicist Lisa Randall put it in the title of her recent book about particle physics.

But what if nobody answers? What if there is nothing new to discover? That prospect is now a cloud hanging over the physics community.

It’s been five years and more than seven quadrillion collisions of protons since 2012, when the collider discovered the Higgs boson, the particle that explains why some other elementary particles have mass. That achievement completed an edifice of equations called the Standard Model, ending one significant chapter in physics.

A 2015 bump in the collider data hinted at a new particle, inspiring a flood of theoretical papers before it disappeared into the background noise as just another fluke of nature.

But since then, the silence from the frontier has been ominous.

“The feeling in the field is at best one of confusion and at worst depression,” Adam Falkowski, a particle physicist at the Laboratoire de Physique Théorique d’Orsay in France, wrote recently in an article for the science journal Inference.

“These are difficult times for the theorists,” Gian Giudice, the head of CERN’s theory department, said. “Our hopes seem to have been shattered. We have not found what we wanted.”

The particular thing many physicists wanted was supersymmetry. Supersymmetry is a theory that fixes some mathematical problems with the Standard Model by positing an entire suite of particles "symmetric" to the more familiar ones, but at much higher energies. Some versions of the theory posit that some of those particles should have showed up in the CERN data by now. They have not, leading to what one researcher called "a massacre of theories."

The physics we have provides all the knowledge we need to get on with high-tech civilization, but it doesn't explain the universe. The hope was that CERN's colliders would yield new data that would point toward new kinds of explanations. But that hasn't happened, and physicists don't know where else to turn for answers.